Complimentary PDF Library

Here you will find PDF Docs of the Workshop manual to compliment the sections of this page. You will also find important safety and correct jack and axle stand positions. Always ensure your safety when working beneath a veichle.

If there is more information you require on a subject contained on this page, please feel free to contact me through the 'Links' page.

V6 Camshaft Timing

Camshaft Timing ????

The Mazda V6 'KL' engine only uses two camshaft pulleys, these are connected to the ends of the front bank Exhaust Camshaft and the rear Inlet camshaft. Each of the 4 camshafts has a gear by which they interlock into pairs and they have to be interlocked in their correct positions. Failure to do so will result in the valves not being open/closed (timed) when they should be and the engine will not run, or run very badly !

On many occasions people have overlooked this one procedure, resulting in a full head strip down once again to correct the problem, a timely and expensive practice.

Also note that each camshaft is stamped with a number, this represents their correct position in the head. KL01 - 421, 431, 441 & 451.

421 = Rear Inlet cam

431 = Front Inlet Cam

441 = Rear Exhaust Cam

451 = Front Exhaust cam (also has slots on the end for the distributor)

When should this be done ?

Whenever the Camshafts are removed from the cylinder head. Unlike pulleys on a belt, the interlocking gears cannot 'slip', once set, they stay.

Checking the timing

First set the engine to top dead center. It just so happens that with the engine set to this position, the cam timing marks will be visable, and show if correctly installed. With the Cam covers removed and the thrust cap covering the camshaft gears removed, you should be able to see the rear face of the cam gears. The rear face of each camshaft gear has a 'punch dot', these should be in alignment when they pass each other.

Setting the Timing

If installing the camshafts, it is imperative you present the camshafts together to the cylinder head, keeping the dots in alignment and in the same positon as per the diagram. Doing so keeps the camshaft lobes off the HLA's allowing the camshafts to drop into place. The camshafts are a tight fit initially and may not want to seat into their journals, some light persuasion and jiggling should get them to drop, ensure the dots are still aligned.

Once they have dropped into place, keep the camshaft dots aligned as per the diagram. Failure to do so will mean the cam lobes are in contact with the HLA's, and when you come to tighten down the journal caps, the camshaft could well snap in half ! or you will ruin the journals within the cylinder head.

De-Carb Procedure

Partial Work-Around

Design fault only on earliest KL V6 engines with engine #s pre KL326296, pre 08/03/93. Mazda TSB B00995/95, issued 16/06/95, re 626/MX6/Probe-2.5.


Diesel-like sound on winter cold-start, diminishing quickly as the engine warms (sounds like frozen peas bouncing off pistons).


Carbon-build up causes "carbon-knock", tackle when heard. The noise is not HLA/Lifter ticking, nor the (aesthetic) Friction Gear noise localised around the exhaust cam of the rear V6 bank, timing belt end and dissappears at circa 2200rpm.


Simple decarbon service at ?70/70$US, common for many engines with modern fuels.

TSB solution, #96113, May 96
  • Bring engine to normal operating temperature, then shut engine off.
  • Use a 610mm (?!) length of 1/8" I.D. vacuum hose as a feed tube for carb cleaner (Carburetor Tune-up Cleaner, ford # D9AZ-19579-BA), although it is strongly advised to use an aerosol cleaner to eliminate the risk of liquid lock (some techs have done it). Do not use any of the vehicle's vacuum hoses for feeding cleaner into the engine otherwise they may deteriorate as a result (vacuum leaks on 24 possible hoses is tedious).
  • Connect one end of the feed tube to the Purge Control vacuum port on the upper intake manifold and place the other end of the feed tube in the can of carb cleaner, or to the spray nozzle of an aerosol. If a liquid bottle is used the feed rate must be at least 30 secs to avoid hydraulic lock-up damage.
  • Pinch the feed-tube with locking forceps or locking pliars to prevent suction during start-up.
  • Restart engine.
  • Allow idle to stabilise, then feed the cleaner into the engine by releasing the locking pliars/forceps while lifting engine speed to 3000rpm until half the cleaner is used. If using liquid feed, ensure feed-rate is always erring on the safe side by kinking the tube (a thumb screw clamp is ideal). If using a spray feed (preferred) keep shaking the can vigorously. At the half point allow the engine to stall, or shut-it off.
  • The vehicle should be left to sit for 6-24hrs allowing the cleaner to saturate the carbon, the initial intake of cleaner loosens carbon by both dissolving and also by a cold-shock.
  • Flush remaining carbon by repeating the above steps using the remaining half of the carb cleaner. Do not let the engine stall during the procedure.
  • Remove the feed tube & reconnect the purge control vacuum line.
  • Change oil & oil filter to remove contaminants & carbon in the oil which will otherwise be pumped through all the HLAs.
  • Take the car on a 3-4 mile test drive, using the full-rpm range to remove any remaining cleaner or carbon from the engine.
  • Let the car sit for another 12hrs, restart - if the noise is gone then the cause of the noise was carbon build-up.
Full Noise TSB re Carbon-Knock/HLA/Friction-Gear

Here is a full TSB re Noise from Carbon-Knock/HLA/Friction Gear, issued by Ford/Mazda :

Page 1 of TSB -:- Page 2 of TSB -:- Page 3 of TSB -:- Page 4 of TSB -:- Page 5 of TSB -:- Page 6 of TSB -:- Page 7 of TSB -:- Page 8 of TSB -:- Page 9 of TSB -:- Page 10 of TSB
Can I use higher-octane fuels for more performance ?

Using high-octane fuels (98/100 RON) has benefits on the V6 engines as they have a knock-sensor to take advantage of it; UK Standard unleaded is 95RON, Super-Unleaded is 97-98RON. However using higher than 95 RON is largely unnecessary (re cost/power).

The ECU automatically adjusts timing based on the knock sensor from 6-18 degrees, a very considerable range. Base timing is 10 degrees +/- 1 degree.

Cars with 2.0 engines, like Miata/MX5s, do not have knock sensors and thus can't take advantage of higher-octane fuels without adjusting their timing. The miata/MX5 groups often do this, but there is no safety back-track if pinging does occur due to carbon-buildup (on any engine) or simply poor quality gasoline a risk of engine damage as a result.


TSB = Technical Service Bulletin : The specific Carbon-Knock TSB refers to 'customer satisfaction'; some mechanics say if untreated long-term then valves could be damaged (burnt). Decarboning is an easy & relatively cheap service to performand benefits any engine, not just those early V6s whose head design allows carbon to build-up in an area where it will create noise.

OBDI Ignition Timing


The early models running on the OBDI engine management system, had a primary ignition timning. Once the engine has started the engine management system kicks in and takes over using the base timing as a reference and adjusting where required for the optimum engine performance through out the rev range. The Later OBDII system does not require the initial timing to be set, and there are no ignition timing instructions for the OBDII system.

Tools Required

12mm Spanner and socket, Strobe timing light, white marker i.e Tipex, phillips/crosshead screwdriver, 19mm spanner/socket, paperclip.

Setting the timing
  • Bring the engine to its normal operating temperature
  • Open the hood/bonnet and locate the black oblong diagnostic connector behind the battery with "DIAGNOSTIC" printed in raised type on the top.
  • Within the lid you will see a diagram of the pin connections. Locate the terminals "TEN" & "GND", notice there is a "B+" terminal nearby which is a 30A +12V feed from the battery and no loose strands of wire must touch it.
  • Take the paperclip or some insulated wire, approximately 2.5mm^2, and strip off 1/4"/0.5cm of insulation from each end. Form the clip/wire into a loop about the middle to create a jumper-wire. Solid wire is preferred.
  • Connect this jumper-wire across the connections labled "GND" & "TEN". Ensure no other connectors are connected, and no strands are wandering about if stranded wire is used.

What you have just done is disable the ECU from managing the engine through the data collected by the sensors. When the engine is started it will be running without any assistance at all from the ECU. It is imperative you disable the ECU when setting any base adjustments.

If the cooling fan kicks in as soon as you start the car, it is an indication that your TPS is not set correctly, see the TPS setting procedure on this page. This needs to be rectified before proceding any further with this section.

If the Cooling fan kicks in as normal due to overheating whilst performing the timing operation, allow it to stop before proceding. The power drawn by the fan will affect the idle speed and therefore the timing.

  • The distributor is held in place by 2 x 12mm bolts, one at the top and easily accessable, the other is at the bottom and easier to access with a short extension bar and 12mm socket
  • Loosen these 2 bolts just enough to allow you to twist the distributor.
  • Now connect your strobe/timing light to the No.1 cylinder ignition lead. No.1 Cylinder is the top left of the 6 cylinders as you look at the engine, plus your distributor cap should be numbered at the connections.
  • Ensure the handbrake is on, no gear is selected, and start the engine.
  • If the engine will not stay running, then the idle air screw ontop of the throttle body will need to be opened a little more with the possi-drive (The ecu has been compensating for this problem).
  • With the engine running, point the strobe light down towards the crank pully, dipstick end of the engine and between the engine and inner wing.
  • You should be able to see the notch in the pulley, and the -20 to +10 measurement indicator showing a 10 and 'T'. If the notch in the pulley is not easily seen, then stop the engine, use the 19mm spanner/socket to rotate the crankshaft pulley clockwise until you can see the notch and then apply a little marker paint. Restart the engine.
  • If the notch in the pulley is not aligned with the '10' marker +/- 1, then slowly twist the distributor until it aligns.
  • Now check the idle speed, it should be 650 rpm +/- 50rpm
  • If the idle speed is too High, then very slightly turn the idle air adjustment screw clockwise until the desired idle speed is shown, too slow, turn anti-clockwise.
  • Now check the pulley notch once again with the strobe/timing light. If you had to adjust the idle speed, you will most probably find the notch has moved.
  • Re-align the notch, check the idle speed, adjust, check notch again. Continue this process until the idle speed is as desired and the notch stays on the '10' marker.
  • Once its set, very gentley tighten the top bolt of the distributor to lock it down. Then check the notch still aligns incase you disturbed the distributor when tightening.
  • Switch off the engine.
  • Tighten the bottom bolt of the distributor, remove the strobe light, and remove the jumper wire from the diagnostic box.
  • The base timing is now set.

This procedure is best performed with new spark plugs, HT leads, distributor cap and rotor arm. If any of the fore-mentioned parts are renewed then the process should also be carried out, as they are bound to affect the timing.

Mechanical Timing


To ensure the Pistons and Valves are working in harmony and where they should be in relation to each others position during the cycle.

This procedure is required when replacing a Drive Belt, or ensuring the drive belt has not slipped due to stetching/age or tensioner not working correctly. The procedure that follows runs through the replacement of the Drive-belt. If you are investigating the possibility that your drive belt has slipped, this procedure shows clearly the timing marks and how the pulleys align.


The procedure that follows was created by Probetalk memeber 'Leska' and full credit goes to him. I have also incorporated some clearer pictures of which were taken by, and full credit to, 'OmahaPGT' over at

The following is information and photos regarding the repair procedure as well as replacing the idler bearings for the timing belt and accessory belts.

Loosen crank & water pump pulley bolts
  • Before jacking up the car, turn the wheels to the RIGHT and pop out the rubber plug in the splash well(it may already be missing on older cars). The crank bolt is directly accessible inline with this hole, as pictured here...
  • If you have a manual transmission, select 4th gear and set the parking brake firmly. The bolt can easily be broken loose witha breaker bar.
  • If you have an Auto transmission, you will will have to brace the breaker bar against the frame rail and 'tap' the starter to crank the engine and pop the bolt loose.
  • Whilst the car is stil on the ground with all the belts on, take a 10mm combination spanner and crack loose the 4 bolts on the water pump pulley. Its much easier to do it now whilst the belts are still in place holding the pulley(s) still.

Removing the AC and Alternator Belts
Air-Con Pulley
  • This belt is tensioned with a pulley that is forced down via a long bolt and thread. You must loosen the 17mm locknut on the pulley and then you can turn the 10mm adjustment bolt anti-clockwise to raise the pulley off the belt. Once the pulley is fully loose, remove the locknutas well as the pulley itself.

Note : The lock nut for the pulley is somewhat difficult to access. One method is to use a 1" combination wrench turned sideways over the end of the 17mm wrench for leverage. As pictured...

Remove Wires

Behind the coolant cap above the water pulley are two coolant-related sensors that pass over the belt area. There is also the Crankshaft Position Sensor (CPS) connector right under the radiator hose. Disconnecting these is not required, but it certainly makes it easier. Push them out of the the way once disconnected. The Ford manual recommends removing the upper radiator hose, but this really isn't necessary

Optional : Remove Spark Plugs

This is not a requirement to do the belt. However, the engine will rotate freely without the plugs installed and no compression. This is very nice for turning the crank and cams by hand later in the procedure for alignment.

Raise and support the vehicle

PLEASE ensure you use the 'Safety Information' PDF supplied for the correct positions for jacking and supporting the vehicle. Never work beneath a car supported only by a jack.

Remove the lower splash guard
Splash Guard

The lower engine splash shield must be removed (if still fitted). There are an assortment of bolts and snap clips used to hold it on. Remeber to push the center of the plastic rivets inwards to unlock them before atempting to remove them. The center must be pushed out past the rivet surface to reset them for installatio.

The Shield and bolt holes can be seen in the adjacent picture...

Remove Power Steering Belt & Adjuster
Power Steering Pulley bolt

Once the splash shield has been removed, you will have easy access to the other belt adjuster. As with the AC/Alternator Pulley, Crack the 17mm lock nut loose and then turn the 10mm adjuster rod until the belt is loose. Remove the lock nut and the pulley completely, also remove the belts.

Remove the Crank Bolt & Pulley
Crankshaft Pulley

Now that the belts have been removed and the pressure is off the crank pulley, remove the crank pulley bolt and wobble the pulley back and forth until it loosens up and slides off. In many cases, the pulley will need to be carefully proed off with tools. If necessary, place suitable pry bars behind each side of the pulley and force it off. Be carefull not to damage other parts or the crank position sensor, or the pulley itself. Sometimes its helpful to smack the lip of the crank pulley a few times with a rubber or rawhide mallet to break it loose. The pulley is keyed to the crankshaft and gets rusted on.

The parts can be seen in the picure opposite.

Remove the Water Pump Pulley
Current position

At this point, if you have been following my instructions, you should be in the same positon the picture to the right depicts... and you can remove the bolts with your fingers and remove the pulley.

Optional : Remove Power Steering Pulley

This is not a requirement, but it makes getting the timing covers off much easier. (orig) A suitable bar can be inserted in the spaces within the pulley to hold it in place, (Ed. Through the spaces in the pulley, you will see on the right hand side one of the bolts used to hold the power steering pulley bracket in place, insert a suitable sized socket (12mm i think) through the hole and let it seat on the bolt, due to its length, it will pertrude through the pulley and can be used to hold it in place whilst loosening the pulley bolt.)

I've done this job both ways and its much better without the pulley in place.

Remove Cover / Bracket Bolts
Alternator Pulley & bracket

The timing cover 10mm bolts can now be removed from the lower end of the covers. There are two bolts on the outside of the left cover, two bolts on the right outside (one has the CPS wire support) and one directly above the crank pulley.

Remove the bolt that supports the oil disptick tube and remove the tube by pulling upward carefully to dislodge the 'O' ring without damaging it. Plug the hole with something suitable to prevent dirt from falling into the oil pan.

Now remove the upper accessory belt support bracket. There are two bolts that hoold the bracket in place..One long bolt on the top and a short one at the bottom. It looks like the picture opposite

Next, remove the upper cover 10mm bolts. There are three around each of the cam sprocket (be prepared to fight for the bolt on the bottom rear edge of the rear cam), one in the 'V' of the block and another on the rear(left) cover in a similar place as the oil tube bolt on the right cover. Remove the covers.

The bolt hole locations can be seen in the picture opposite.

Drivebelt covers
Remove Engine Mount

Remove the three 17mm nuts on the enigne mount. There is a ground wire clamped between two of the nuts. The enigne will fall slightly as the mount is loosened, however the engine will not fall down due to a tab on the support bracket. I like to put a 2x6, or suitable piece of wood, under the oil pan and gearbox and support the engine with a trolley jack anyway (Ed. DO IT !). Just keeps the stress off the other parts.

Engine mount bracket

Remove the 17mm pinch bolt that connects the center of the mount to the body. It has a tab on the nut that keeps it from turning, so just just loosen the front side, remove the mount.

Next, remove the engine side of the mount which is the support bracket. There are three bolts that attach this to the block, this can be seen in the picture opposite...

Align Crank and Cams
Crank Sprocket Alignment

If you are just replacing the belt, turn the engine clockwise by the front cam sprocket center bolt with a 17mm wrench or socket. If you removed the spark plugs, then this is easy to do, if not .. maybe now is the time to do so... Turn the engine until both cam and crank marks line up. For those of you who are new to engine work, remeber this will only happen every two rotations of the crankshaft.

For those replacing a broken belt, the KL series engine is a non-interference motor. The pistons will not collide with the valves when turning independently, especially by hand. Align the marks as per the pictures shown.

The crankshaft marks are a triangle shape at 12 O'Clock on the engine block and a 'U' shaped notch on the sprocket. Note in the picture, the crank is turned slightly so the 'U' is just to the left of the 'triangle', this is required for the belt install.

The cams are aligned by a 'Triangle' shaped mark on the cylinder head and a circle punched into the cam sprocket that usually has coloured paint on it, as shown in the pics to the right.

Rear Camshaft Sprocket    Rear Camshaft Sprocket    Front Camshaft Sprocket    Front Camshaft Sprocket
Timing Belt Hydraulic Arm Removal

This is the infamous part that fails and allows a knocking noise to happen. There are two bolts that hold the tensioner arm in place. Take the bottom one out first. Once the tensioner has been removed, throw it in the bin and replace it with a new one. Although its very expensive, it does not make sense to re-use this if it has any substantial miles on it. If for some reason you are removing a newer part, you need to compress the post back into the arm with a press or vice, very slowly and straight. Hold the post in place with the lower of the two holes when aligned, with a drill bit or large sewing needle. See the picture.

Remove the belt. If you are installing the same belt as it does not have many miles on it, be sure to mark the direction it was installed. Never install a belt backwards, the fibers within the belt tear.

Optional : Water Pump Replacement

If your water pump has never been replaced, and it has a few miles on it, consider replacing the water pump when doing the timing belt.(ED. Although its possible, but fiddly and not recommended, the pump can be swapped out without removing the belt. As a moderator and helper over at, I always advertise to replace the pump at EVERY belt change. You can see the amount of work required just to get to this stage, do you really want to have to do it all again just to replace the pump should it fail 3000 miles after changing the belt ? ).

Note there are two types of pumps for the KL V6, one with a 32mm pilot hole for the pulley, and the other with a 16mm pilot hole. Before purchasing the part, simply look in your engine compartment at the pulley to verify which one you have. The pilot sticks out through the pulley. The timing belt does nto have to be removed to swap out a water pump, but it can be tricky fitting the pump in without messing up the new water seal on the pumpwhilst trying to avoid the timing belt parts.

Coolant Drain Plug

Drain the coolant : Remove both coolant caps, place a pan under the drain valve and loosen the plug see in the picture...

Remove the pump : Remove the 5 remaining pump bolts and remove the pump. Make sure all the rubber 'O' ring seals came off with the pump. Both parts look as per the pictures.

Clean the mounting surface : Clean the pump mounting surface on the engine to remove corrosion which looks as per the picture. I prefer to use a mild 3M scotch-brite pad and then follow with a 600 grit aluminium oxide paper for a smooth finish and a good seal. I use brake cleaner to remove all residue.

Install the pump : Place new 'O' ring on the new pump and carefully position the pump on the engine. Although some like to use silicone sealant, I dont like to use it on rubber 'O' ring seals. Every other gasket is great with permatex, but not 'O' rings. I've seen many leak that were encased in silicone sealant. Its a bit tricky getting the pump in place without dropping the seal, but we do this for the sport as wellas the glory .. right ? (ED. Depends if your lay under the car in the pissing rain and gale force winds, maybe just a spot of sealant just to hold it in place during fitting ?)

Install the 5 bolts (remember the engine mount takes up one hole) and tighten to 14-18 LB-FT. Refil the cooling system once the car is back on level ground. Remeber to fill by the cap on the engine, not the expansion tank near the battery, otherwise you will have trapped air.

water pump facewater pumpwater pump
Optional : Bearing Replacement

If your like me and love a quiet engine, you'd probably like to replace bearings when at all possible if they were cheap, right ? Well here you go, I replaced all the bearings in the timing belt idlers and the car sounds fantastic, just like new with 138k on it !

Each idler has 4 parts to it, a core piece, TWO bearings and the outer shell. The idlers are in the $160 price range EACH from Ford or Mazda. The bearing thenselves have the number NSK 6006DWA on them. The 6006 Bearing is very common, but not the DWA distinction. In fact, no one (even NSK reps) had ever seen a DWA on a bearing. I finally got a guy to call NSK Japan office. They found it was a special seal design for automotive use with 40% less seal drag, and of course... you cannot buy them !

So now what ? Here is my solution that works well. The factory idlers have two bearings pressed face to face with the inner seals removed (less drag i would immagine). I decided to use a standard 6006 on the outside bearing and a 'No-Contact' type 6006 on the rear. My theory is the rear of the idlers were very clean and easily covered in dust.. and 100% seal drag + 0% seal drag puts me 10% better than OEM. I pried off the inner seals like the factory did before pressing them back in. Each standard 6006 was $16 (at time of original write up) and the 'No-Contact' 6006 was $12 (at time of original write up)

They look like this...

Idler bearings

Bearing replacement : You have to be creative here if you dont own a press. I used a variety of wood blocks and sockets to drive out the core and then the bearings. I braced the flanged part of the shell on four pieces of plywood while pounding out the bearings. Use a wood block and sledge to drive the bearings back in by the outside shell (to protect them). Make sure to pry off the inner seals before installing them. Lube the surface of the bearing with something light, like liquid wrench to make puching them in easier. This is really the best money ever spent on my car.

Why stop there ? I asked myself the same thing. Why not do the accessory belt tensioner pulley bearings too ? These are definately easier to pop out and press in with a socket. Replacements were $4 each (at the time of original write up) . Once again, they had a special seal marking for lower drag, but the standard bearing of that size had almost the same measured drag. Both pulleys use the same bearing.

They look like this...

Accessory pulley bearings
Back to the timing Belt !
Timing Belt Install
Crankshaft Sprocket

Verify crank and cam marks are aligned as shown above

Rotate the crankshaft anti-clockwise one tooth like in this picture on the right...

When installing the new belt, make sure that you can read the writing on the belt from the same side of the engine, and not have the writing upside down. Some manufactures optimize the tooth aignment for noise reduction. Slide he belt on while making sure not to rotate anything. Then turn the crank forward one tooth (match aligning marks) without moving the cams to put all the belt slack on the tensioner side of the crank.

Install the tensioner arm : Tighten the bolts to 14-18 LB-FT and remove the pin holding the pushrod. Check the timing belt tensioner pulley bolt for 28-32 LB-FT.

Verify Alignment : Turn the crank two full turns, 720 deg, clockwise and verify all timing marks still align on the camshaft sprockets and that the 'U' notch on the crank now lines up with the triangle.

  • Install the mount bracket with its three bolts and tighten to 32-44 LB-FT
  • Install the plastic timing covers and tighten all the 10mm bolts to 71-88 LB-IN (note thats INCH POUNDS, LB-IN, not FOOT !). Remember to remove the plug and install the dipstick tube with the middle right bolt and the crank position sensor wire bracket with the lower right bolt. Install the upper belt tensioner bracket with its 2 bolts, tighten them to 14-18 LB-FT.
  • Install the water pump pulley and 'snug' up the bolts, remembering to tighten them to 71-88 LB-IN once the car is complete and back on the ground.
  • Install the power steering pulley if removed and tighten to 36-43 LB-FT.
  • Install the crank pulley and 'snug' the bolt until the car is back on the ground and then tighten to 116-122 LB-FT.
  • Install the pulleys on the adjusters, install the belts and turn the 10mm adjuster rods until the belts are tensioned. Remember, you can always tighten them more later. Pull or push on the center of the belts and see if you can flex them with moderate pressure about 1/4". Tighten the 17mm locknuts.
  • Install the splash shield.
  • Install the engine mount, not forgetting the ground wire between the two left nuts. Tighten to 54-76 LB-FT. Tighten pinch bolt to 50-68 LB-FT.
  • Reconnect coolant sensors, crank shaft position sensor and install the spark plugs if removed.
  • Refil with coolant if water pump replaced. Check for leaks

Throttle Position Sensor (TPS)


Provides the ECU with data regarding the positon of the throttle butterfly and just how much peddle you are applying.

Known Issues

Many a poor idle has been traced back to a badly set TPS. Poor acceleration issues and non-working of VRIS solenoids due to the ECU not knowing the amount of throttle being applied.


There are a few ways to set the TPS, from quick and simple to more elaborate and specifc. This section will cover them all.

The Quick Fix

Undoubtably the quickest way to set the TPS postion is the 'coolant fan' method. This method however is not an exact setting, as the ECU works off voltages sent to it. The procedures that follow this one are more exact and specfic to setting the TPS.

  • Open the hood/bonnet and locate the black oblong diagnostic connector behind the battery with "DIAGNOSTIC" printed in raised type on the top.
  • Within the lid you will see a diagram of the pin connections. Locate the terminals "TEN" & "GND", notice there is a "B+" terminal nearby which is a 30A +12V feed from the battery and no loose strands of wire must touch it.
  • Take the paperclip or some insulated wire, approximately 2.5mm^2, and strip off 1/4"/0.5cm of insulation from each end. Form the clip/wire into a loop about the middle to create a jumper-wire. Solid wire is preferred.
  • Connect this jumper-wire across the connections labled "GND" & "TEN". Ensure no other connectors are connected, and no strands are wandering about if stranded wire is used.

What you have just done is disable the ECU from managing the engine through the data collected by the sensors.

  • Turn the ignition to 'ON' (not start the engine)
  • If the coolant fan kicks in straight away, then your TPS is not set correctly.
  • If the TPs needs adjusting, using a phillips screwdriver, slacken off the two screws holding the TPS in position just enough to allow it to be moved.
  • By rotating the TPS Clockwise / Anti-Clockwise you are looking for the 'sweet spot' where the fan just turns off, try it a few times and you will find the spot where the fan kicks in, you then need to very slowly backtrack to the point it just turns off.
  • Tighten the 2 screws holding the TPS in positon.

Congratulations, you have just set your TPS the easy way, albeit not quite as accurate as can be done, but it will see you through until you get around to one of the more specific ways of setting it.

Specific 1 - The voltage way

This particular write-up was created by probetalk member mvaughn1 and full credit and thanks goes to him, so without further ado..

The "TPS adjustment" is aimed at properly tuning the idle and throttle response that is often out of whack and instable in a car that has had a throttle body modification or just needs adjustment.

I know when I first started doing this I was confused as to what exactly to do and how to do it. I've got a few pics that will clear this all up. Here it goes:

Tools Required :
  • Multimeter or Volt meter capable of 2 decimal places.
  • Large and Small phillips screwdrivers.
  • A needle / long pin.

First, an overall shot of the engine to show you exactly where the TPS is

Throttle Position Sensor Location

  • Here's a close-up of the TPS. With the motor turned OFF, put a needle into the yellow wire as illustrated here :

Tapping into the data wire

Here's an extreme close-up of the needle

Tapping into the data wire

  • Plug the wire harness back into the TPS and turn the ignition switch to the "ON" position.
  • Get your multimeter and plug the (+) probe to the needle and the (-) probe to your neg. battery terminal as is illustrated here :

Setting up the multimeter

  • Get a phillips screwdriver and close your throttle screw on top of the throttle body all the way closed.
  • You may be able to keep it all the way closed and start the car, but you may need to open a bit before the car will idle.

You want to use this screw to set your idle at around 700 rpms). You also want to have that small screw on the actual throttle cable pivoting arm not touching anything. Here's a pic to explain :

Setting the idle air screw

  • Set the meter to volts, mine is at the 20v setting which gives 2 decimal places which is sufficient. You need two decimal places because the tuning may be affected by .01 increments but more likely about .04-.05 increments will give you noticeable differences in most cases.
  • Turn the ignition to "ON" but don't start the car. Do not put the car into diagnostic mode. Work with your initial setting by going up/down in .05 increments.

There seems to be no "magic setting" that is perfect. I've run mine as low as .27 and high as .85 and the car ran each time, just sometimes idle was high or inconsistent and there was a missing and momentary hesitations at partial throttle. I am currently using .65 and it is perfect. NDFRSPD_PGT is a local buddy of mine whose car runs great at .75. You will NEED to experiment to find the setting for your car.

  • To actually adjust the TPS, loosen the screws with a screwdriver or small socket if you prefer but leave just tight enough to keep in place but able to rotate a bit. Here are the two screws I mean, and you can see how the TPS actually rotates up and down around the screws :

Setting the idle air screw

THAT'S IT!!! It's very easy, and I have seen personally upwards of 5 cars or so that have gone from a poor lopey idle, misfiring at throttle, and slow throttle response to running like the day they rolled off the dealer's lot. Having said all that, some people claim to have done this and it didn't make a difference. I think that you'll find if you follow these steps and don't get frustrated it'll improve your car if it needs it.

Specific 2 - The Coolant Fan and throttle stop way
Setting the idle air screw

This particular write up was created by RSP Motorsports, and full credit must go to them.

Caution : When following these instructions and using the images as GUIDELINES, make sure you jumper only stated pinouts. Regardless of actual location in your diagnostic box. Consult your car specific model year for exact pinout locations.

The engine must be at normal operating temperature before performing this procedure.

OBD & OBDII diagnostic box's may differ in pinout location.

To many times I hear of owners of the KL series engine who have idle quality issues. This could be one or more of several sensors/devices improperly set or malfunctioning. The following procedure may or may not resolve this issue, but in the least its a root cause analysis procedure that can eliminate the TPS as a cause. The TPS, located at the front of the throttle body(TB), is the Throttle Position Sensor (TPS). This sensor relays throttle position specific information to the ECU to keep the motor running correctly throughout the RPM range.

Tools Required
  • Phillips head screw driver
  • 1/4" metric socket set
  • Jumper wire, 3-6" long capable of handling a 12v circuit.
The Adjustment Setting the idle air screw
  • Turn engine off
  • Loosen the two screws that hold the TPS in place, but keep them snug enough to manipulate the TPS so it will not rotate from its position.
  • Turn the Idle Air Screw in until fully closed, no pressure.
  • Turn the Idle Air Screw open 3 FULL TURNS,Be exact.
  • Adjust the Throttle Position Screw to minimum contact on the throttle linkage, maybe .010-.015" contact at most. See note A-A and B-B in alpha order in the picture.
  • Insert jumper to TEN & GND pin outs in the diagnostic box.
  • Start engine, it may stall, if so, adjust the Idle Air Screw open 1 more FULL turn. Restart engine is necessary.
  • Adjust the TPS, rotate it clockwise/anti-clockwise until the coolant fan comes on. If its already on, rotate until the fan is off. Go through this procedure a few times finding the exact point where the fan turns on and off. Set it to just when the fan is off.
Setting the idle air screw
  • Adjust the Idle Air Screw until the idle is about 350-400 rpm's (turn - closed(cw)/open(ACW) until idle is as stated, should be in the CW rotation).
  • Tighten the screws for the TPS.
  • Turn off engine.
  • Remove jumper wire from diagnostic box.
  • Remove NEGATIVE battery cable for a minimum of 60 seconds. NOTE Ensure you have set your Car Alarm to valet mode(if it has one) or disabled and that you have any necessary codes for radios etc. before disconnecting the battery lead.
  • Reconnect battery cable
  • Restart engine.

The idle should now be at 650-700 rpm's, if not, continue..

Before continuing, make sure the throttle body butterfly is adjusted as described above. Manually adjust it to the closed position if necessary, then readjust as described above. If readjustment is needed, restart the entire procedure.

To adjust the idle use the Idle Air Screw located at the top back of the throttle body. Turn the screw clockwise(cw) or Anti-Clockwise(ACW) to increase or decrease the rpm. Set the idle so it reads approx 650-700 rpm.